PURPOSE: To clarify the morphologic and quantitative changes of mechanoreceptors of the human ACL with degenerative arthritis. MATERIALS AND METHODS: Eleven fresh specimens of anterior cruciate ligament (ACL) were obtained from patients with degenerative arthritis during TKA. As a control, two fresh specimens were taken from healthy men at the time of a traumatic above knee amputation. The whole ligaments were serially frozen and sectioned at a thickness of 40 mum. After immunohistochemical staining, the mechanoreceptors were observed under a light microscope. The ratios of sections showing mechanoreceptors were calculated. Statistical analyses were performed using the chi-square test. RESULTS: In the two control specimens, nineteen mechanoreceptors were found, evenly distributed at the femoral and tibial ends. However, the average number of mechanoreceptors was 1.4 (total 15) in the arthritic ligaments (p<0.05), and these were located near the femoral side rather than the tibial end. The percentage of sections showing mechanorecptors was 8.3% in the arthritic group and 40.2% in the control group (p<0.05). All receptors were round or fusiform shaped Ruffini corpuscles; Pacinian corpuscles could not be found in either group. Nine of 15 mechanoreceptors in the arthritic groups were "necrotic" in shape. CONCLUSION: Mechanoreceptors in arthritic ACL were significantly reduced in number and mainly necrotic in shape. Our findings suggest that the numerical and morphological changes of mechanoreceptors are closely related with reduced proprioception in degenerative arthritis.
Amputation ; Anterior Cruciate Ligament* ; Humans ; Knee ; Ligaments ; Male ; Mechanoreceptors* ; Osteoarthritis* ; Pacinian Corpuscles ; Proprioception

Pacinian neuroma is a rare tumor characterized by hypertrophy and hyperplasia of preexisting pacinian corpuscles. This tumor most frequently presents as a small superficial mass affecting the hands and feet, which produces localized sharp pain. The etiology is unknown, but local trauma has been postulated as an important factor. Here we report a case of posttraumatic pacinian neuroma in a 24-year-old woman who presented with severe local pain in the palm. The clinical features, and the sonographic and pathologic findings of posttraumatic pacinian neuroma are discussed.
Female ; Foot ; Hand ; Humans ; Hyperplasia ; Hypertrophy ; Neuroma ; Pacinian Corpuscles ; Young Adult

Pacinian neuroma is a rare skin disease characterized by hyperplasia or hypertrophy of the Vater-Pacini corpuscles which are responsible for the appreciation of deep pressure and vibration. It usually affects the volar aspects of the fingers in middle-aged adults and it produces severe pain and tenderness on the affected skins. About half of previously reported cases revealed the association with precipitating factors such as local trauma, but underlying mechanisms are not established. Two patients presented with a several months history of solitary pale-colored papule on the tip of finger. The patients reported a severe tenderness on the lesion with a history of repetitive trauma. The histopathologic examination from the lesions showed increased number of onion-like stratified structures around nerve fibers, compared to the usual density of pacinian corpuscles (3~5/cm2). The histopathological features were consistent with pacinian neuroma. The symptoms of the patients disappeared soon after the surgery. Herein, we present two patients with pacinian neuroma on the finger, and we also propose that pacinian neuroma should be considered for the differential diagnosis of tender papule on the digit.
Adult ; Diagnosis, Differential ; Fingers* ; Humans ; Hyperplasia ; Hypertrophy ; Nerve Fibers ; Neuroma* ; Pacinian Corpuscles ; Precipitating Factors ; Skin ; Skin Diseases ; Vibration

Pacinian neuroma, also known as hyperplasia and/or hypertrophy of pacinian corpuscles is a rare skin condition usually occurring in the hand. Although it is known to cause pain and tenderness on the affected skin, asymptomatic cases have also been reported. We report a 46-year-old male monk who presented with asymptomatic skin lesions of paler color than the adjacent normal skin on the tips of the fingers of both hands. The 3 mm punch biopsy conducted on the lesion showed an increased number of onion bulb-like structures with a nerve fiber in each center. The patient was diagnosed with pacinian neuroma and has been under regular follow up without treatment.
Biopsy ; Fingers ; Follow-Up Studies ; Hand ; Humans ; Hyperplasia ; Hypertrophy ; Male ; Middle Aged ; Nerve Fibers ; Neuroma ; Onions ; Pacinian Corpuscles ; Skin

PURPOSE: To identify sensory nerve endings in the human hip joint capsule and in the pseudocapsule after total hip replacement. MATERIALS AND METHODS: Ten hip joint capsules from patients undergoing bipolar hip replacement for acute femoral neck fracture, and six pseudocapsules from patients undergoing revision hip surgery for failed total hip replacement were harvested and stained in bulk using a modified gold-chloride method. Sensory nerve endings were identified using the criteria described by Freeman and Wyke. RESULTS: Three morphologically distinct types of nerve endings were identified in the normal human hip joint capsules; type I Ruffini corpuscles, type II Pacinian corpuscles and type IV free nerve endings. In contrast, no proprioceptive nerve endings (type I and II receptors) were observed in pseudocapsular tissues. A small number of type IV receptors were noted in the pseudocapsule, but these were significantly fewer in number than in normal hip capsular tissue. CONCLUSION: The pseudocapsule that forms after hip replacement surgery may protect joint stability through a mechanical check-rein effect rather than through a proprioceptive feedback mechanism.
Arthroplasty, Replacement, Hip* ; Capsules ; Feedback, Sensory ; Femoral Neck Fractures ; Hip Joint* ; Hip* ; Humans* ; Joints ; Mechanoreceptors ; Nerve Endings ; Pacinian Corpuscles ; Sensory Receptor Cells